【作者】 田甜；

【导师】 胡宗海；

【作者基本信息】 北京邮电大学 ， 电子科学与技术， 2023， 硕士

【摘要】 超表面是一种基于亚波长结构的功能器件,可在平面化的亚波长结构内产生光场相位和振幅的改变,用于主动调谐、偏振控制、波前调控等多个领域。基于光学超表面的超透镜在成像和集成光子学等领域具有巨大应用潜力。与传统光学器件相比,超透镜具有亚波长尺度、体积小、低损耗等优点,在器件的轻量化、微型化等方面具有优势。本工作旨在进行偏振不敏感超透镜的设计和性能评估。主要内容和创新包括:(1)设计了一种“十字形”超透镜单元结构。在波长为905nm时,时域有限差分(FDTD)仿真结果显示该器件结构可实现覆盖2π全范围的相位变化,在单元结构纳米柱高度为500nm、550nm和600nm时,透光率大于85%,最高可达99%,且对入射光偏振不敏感,与常见的“圆柱形”和“六边形”单元结构纳米柱性能相当,也较适于实际工艺加工,丰富了超透镜单元结构的单元库。(2)研究了该超透镜结构在通信波段的不同工作波长处的性能,包括相位的覆盖、聚焦效果以及透射率,检验其广泛适用性。分别进行了在1550nm、1310nm和850nm这三个通信波长的超透镜设计,结果显示透射率分别达到83.2%、79.5%和87.2%,在光通信领域具有不错的应用价值。更多还原

【Abstract】 Metasurfaces are functional devices based on subwavelength structures,which can produce changes of optical field phase and amplitude in the planar structures,and are used in many fields such as active tuning,polarization control,wave front shaping and so on.Superlenses based on optical metasurface have great application potential in imaging and integrated photonics.Compared with traditional optical devices,superlenses have the advantages of sub-wavelength scale,small size and low loss,and have advantages in lightweight and miniaturization of devices.The purpose of this work is to design and evaluate the performance of polarization-insensitive hyperlenses.Key contents and innovations include:(1)A "cross" nanocolumn superlens unit structure is designed.At the wavelength of 905nm,the finite-difference time-domain(FDTD)simulation results show that the device structure can cover the full range of 2π phase variation,and the transmittance is greater than 85%and up to 99%with the height of the unit structure at 500nm,550nm and 600nm,and it is insensitive to the polarization of the incident light.Similar to the properties of common "cylindrical" and "hexagonal" nanocolumns,they are also suitable for practical processing.It enriches the unit library of hyperlens unit structures.(2)The performance of the superlens structure at different working wavelengths of the communication band,including phase coverage,focusing effect and transmittance,is studied,and its wide applicability is tested.The three communication wavelengths of 1550nm,1310nm and 850nm were designed respectively,and the results showed that the transmittance reached 83.2%,79.5%and 87.2%respectively,which has good application value in the field of optical communication.更多还原